Esther Peril's "Rethinking infidelity ... a talk for anyone who has ever loved."

Perel, a licensed marriage and family therapist, traveled the world for 10 years examining hundreds of couples affected by cheating to find out why people cheat, even when they're happy, and what "infidelity" actually means?

She questions whether infidelity needs to be the ultimate betrayal it's perceived to be.

"When a couple comes to me in the aftermath of an affair that has been revealed, I will often tell them this: Today in the West, most of us are going to have two or three relationships or marriages, and some of us are going to do it with the same person," Perel says. "Your first marriage is over. Would you like to create a second one together?"

It may be easier than you think: "For a couple who is no longer sustained, supported by the constraints of tradition, I believe that self-mockery is one of the best means for the relationship to endure," he says.

In this surprisingly convincing talk, Dall'Aglio explains how acknowledging our uselessness could be the key to sustaining healthy relationships.

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Brené Brown's "The power of vulnerability."

Brown, a research professor at the University of Houston Graduate College of Social Work, studies how humans empathize, belong, and love, and her approach to embracing vulnerability and loving whole-heartedly could fundamentally change the way you live, love, work, and parent.

"When we work from a place, I believe, that says, 'I'm enough,' then we stop screaming and start listening, we're kinder and gentler to the people around us, and we're kinder and gentler to ourselves," she says.

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Esther Perel's "The secret to desire in a long-term relationship."

Perel also conducts research around the world on how couples can cultivate long-term sexual relationships. She says in her TED Talk that sustaining desire in a committed relationship comes down to reconciling our need for security and our need for adventure into one relationship.

How do we do this? You have to watch to find out.

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Julian Treasure's "How to speak so that people want to listen."

Treasure, a business sound expert who studies sound and advises businesses on how best to use it, also has some advice for the average person as well. He explains the seven deadly sins of speaking, and his how-to's include vocal exercises and tips on how to speak more powerfully and empathetically.

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Helen Fisher's "Why we love, why we cheat."

Fisher, an anthropologist who studies gender differences and the evolution of human emotions, also knows a lot about love. In her talk, she explains that sex drive, romantic love, and attachment to a long-term partner are deeply embedded in the human brain, but they're not always connected.

"So I don't think, honestly, we're an animal that was built to be happy; we are an animal that was built to reproduce," she says. "I think the happiness we find, we make. And I think, however, we can make good relationships with each other."

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Margaret Heffernan's "Dare to disagree."

Good relationships aren't built on constantly agreeing with each other, as Heffernan, serial entrepreneur and "Beyond Measure" author, explains.

Great research teams, relationships, and businesses allow people to deeply disagree, she says, but "the truth won't set us free until we develop the skills and the habit and the talent and the moral courage to use it. Openness isn't the end. It's the beginning."

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Jenna McCarthy's "What you don't know about marriage."

Fiction and non-fiction author McCarthy writes about relationships, marriage, and parenting, and in her TED Talk shares some surprising research on how marriages really work.